Precision offset spray system for roadway shoulder weed control

A precision offset spray system was developed for use by highway maintenanc e departments for the control of unwanted vegetation in the graded shoulder area adjacent to roadways. The offset sprayer consisted of two fundamental elements: (1) A machine vision system; and (2) a rapid response intermitte nt spray system. This study showed that it is feasible to use machine visio n on a moving vehicle to automatically detect the presence of green plant m aterial and to apply herbicides exclusively to plants and not to nonplant m aterials (e.g., bare soil). The system substantially reduced the amount of herbicide applied to nonplant material. In system tests, there was up to a 97% reduction in applied splay mix over conventional continuous spray appli cations with a plant deposition rate of 57% of continuous spray systems. Im plementation of this technology would allow highway maintenance departments to reduce the cost of weed control and the amount of chemical herbicides r eleased into the environment, while maintaining current levels of weed cont rol efficacy.